Pincheng Luo, Yanxue Lian
PURPOSE: This study examined the independent and combined associations of handgrip strength weakness and asymmetry with incident stroke risk among adults aged ≥ 50 years. METHOD: Data were derived from the Survey of Health, Ageing and Retirement in Europe. Handgrip strength was objectively measured, while stroke was self-reported as physician-diagnosed. Asymmetry was defined using the ratio of left to right handgrip strength based on the "10% rule" and additionally assessed as the absolute difference between hands. Weakness was defined as < 16 kg for women and < 27 kg for men. Participants were further categorized into four groups according to weakness and asymmetry status. Cox proportional hazards models were applied to estimate associations. RESULTS: Among 24 923 participants followed for a mean of 9.6 years, 1839 incident strokes occurred. Handgrip weakness was associated with higher stroke incidence (17.52 vs. 7.29 per 1000 person-years) and a 55% increased risk compared with no weakness. Handgrip asymmetry was linked to a higher incidence (8.15 vs. 7.17 per 1000 person-years) and a 13% increased risk. Each 1-SD increase in asymmetry corresponded to a 2% higher risk. The highest risk was observed in participants with both weakness and asymmetry (18.29 per 1000 person-years; HR: 1.70; 95% CI: 1.35-2.14). Interaction analyses indicated that the joint effect did not exceed the sum or product of individual effects. CONCLUSION: Handgrip weakness and asymmetry independently increased stroke risk, with the highest risk observed when both were present, yet their combined effect did not exceed what would be expected from each factor alone.